PROJECT SUMMARY The long-term goal of this line of research is to understand individual differences in our ability to recognize faces and objects. Prior research has suggested a genetic basis for individual differences in face recognition that is independent from our ability to recognize objects. However, evidence suggests that the ability to recognize objects is well measured by existing methods, and that the relationship between face and object recognition is mediated by experience with objects. In particular, this research seeks to investigate a possible link between the ability to recognize faces and the ability to individuate visually similar non-face objects, given a controlled amount of experience. This relationship is postulated on the basis of prior findings revealing that when people acquire experience individuating objects, they process them as wholes, or holistically, rather than as a collection of parts, and such holistic processing is known to be hallmark of face processing. We will seek evidence for an underlying domain-general ability that supports individuation of visually similar objects for which one has experience, by testing a model in which this ability is expressed across different measures of individuation and across different object categories (Aim 1). During training, participants will learn to individuate visually similar objects within each of four visually distinct categories. Using confirmatory factor analysis (CFA) we will specify and test two alternative models specifying that a superordinate and/or broad factor of individuation ability can be identified that accounts for substantial variance in performance across tasks and categories. Using the best-fitting model from step 1, we will then test whether individuating objects and recognizing faces are related abilities (Aim 2) by conducting a second CFA that links measures of face and object recognition. Understanding the nature of the abilities that are linked to object and face recognition will facilitate prediction in a number of domains where skilled perception is important, including medical diagnosis. It will further our understanding of the underlying mechanisms and neural substrates underlying these abilities and should also facilitate behavioral genetic studies of high-level vision, contributing to our understanding of a hereditary form of a visual face recognition deficit, developmental prosopagnosia, with a prevalence in the normal population estimated by one study to be as high as 2.5%.